The present invention concerns the inerting of aircraft fuel tanks. More particularly, but not exclusively, this invention concerns a method of inerting one or more aircraft fuel tanks. The invention also concerns an aircraft fuel tank inerting arrangement, an aircraft and a software product relating to the same.
It is well-known to those skilled in the art to provide inert gas (typically oxygen-depleted air) to aircraft fuel tanks in order to reduce the likelihood of explosions occurring in the fuel tanks. It is common to provide inert gas to the aircraft fuel tanks during the ascent and descent stages of the flight and not to provide inert air during the cruise stage of a flight. However, such an approach may be rather wasteful of inerting gas and is rather arbitrary in the way in which inerting gas is supplied to the fuel tanks.
US2006/0021652 describes that inerting gas may be supplied to a fuel tank in a more controlled manner, based on measurements of temperature and pressure outside the fuel tank and sensor measurements inside the fuel tank. Unpublished GB patent application no. 1321067.9 describes the supply of inerting gas based on flight parameters, such as ascent rate, descent rate, altitude and attitude, and on sensor outputs, such as the output of gas sensors located in the fuel tank. Such arrangements are based on instant measurements and readings and do not take into account projected aircraft conditions.
The present invention seeks to mitigate one or more of the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an improved method of inerting one or more fuel tanks of an aircraft.